1. Field of the Invention
The present invention relates to an optical touch panel which enables coordinate input by a finger or a pen and includes a display screen (i.e., a coordinate input region), such as a liquid crystal panel or the like, and a light-emitting element, a light-receiving element, and an optical waveguide which are provided around the display screen.
2. Description of Related Art
A known conventional optical touch panel (i.e., a coordinate input device) includes an optical waveguide and microlenses (see, for example, Japanese Unexamined Patent Publication No. 2004-295644). An optical waveguide is light in weight and enables high-speed signal transmission, and is therefore expected to be used in various electronic devices in future. However, such a conventional optical touch panel uses a large number of optical parts, such as mirrors and lenses or the like, and therefore requires complicated assembly and alignment. Further, displacement of such optical parts is likely to occur, and there is a case where high optical transmission efficiency cannot be achieved.
It is therefore an object of the present invention to provide an optical touch panel which includes an optical waveguide, has a small number of optical parts, and is easy to assemble and perform alignment.